In torque and drag calculations, the actual values measured of hook load versus measured depth may not closely correspond to the values expected as the drill string moves farther into a borehole. For each hole section, trial and error calculations of friction factor combinations may be made in order to ascertain an acceptable friction faction for each hole section adequately matching the actual loads and data results. However, trial and error calculations are laborious and prone to human error and thus any method to calculate friction factors quicker and with less error would be advantageous.